1. Field of the Invention
The present invention relates to a communication apparatus. More specifically, the present invention relates to a miniaturized communication apparatus capable of performing communication more reliably.
2. Description of the Related Art
In a noncontact IC (integrated circuit) card system according to a related art, when a user puts a noncontact IC card over a reader/writer, the noncontact IC card receives a magnetic field emitted from the reader/writer and an electromotive force is generated, so that data communication is performed between the noncontact IC card and the reader/writer.
Also, the following communication method has been under consideration (e.g., see Patent Document 1: Japanese Unexamined Patent Application Publication No. 2006-352318). In this method, a human-body communication technique of using a human body as a communication medium is used in the above-described noncontact IC card system, and a reader/writer and a noncontact IC card perform data communication with each other without user's putting of the noncontact IC card over the reader/writer.
A communication terminal apparatus to perform communication in such a communication method is provided with a loop antenna and a noncontact IC communication circuit for noncontact IC card communication; and a human-body communication circuit and a communication electrode for human-body communication. The communication terminal apparatus transmits/receives data to/from a reader/writer via an apparatus performing human-body communication.
At data transmission, the noncontact IC communication circuit receives a signal transmitted from the reader/writer via the loop antenna, and the human-body communication circuit converts the received signal to a signal for human-body communication and transmits the signal obtained through the conversion from the communication electrode. The signal transmitted from the communication electrode is received by an apparatus on the other end of communication via a human body as a communication medium.
On the other hand, at data reception, the communication electrode of the communication terminal apparatus receives a signal for human-body communication transmitted from an apparatus on the other end of communication via a human body, and the human-body communication circuit converts the received signal to a signal for noncontact IC card communication. The signal obtained through the conversion is transmitted via the noncontact IC communication circuit from the loop antenna. Then, the noncontact IC communication circuit receives a response signal from a noncontact IC card via the loop antenna and performs a process in response to the received signal.